This invention relates to round balers, and more particularly to a combination overload and overfill protection system for use in a round baler.
A round baler typically includes a series of side-by-side belts which define a bale-forming chamber. Crop material is supplied to the bale-forming chamber by a pickup mechanism, which picks crop material up off the ground and supplies the crop material rearwardly to a crop inlet associated with the baler. Due to the conditions within which the baler is typically operated, it is possible for the pickup mechanism to engage the ground with excess force or to encounter an object, such as a tree branch or the like, which applies an excessive force to the pickup mechanism. An overload condition such as this can cause serious damage to the drive system of the baler or to other components of the baler.
In addition, a round baler is typically designed to produce bales having a predetermined maximum bale diameter. Once the bale has attained the desired predetermined maximum bale diameter, the operator stops movement of the baler and commences a twine or net wrapping operation so as to finish the bale in preparation for discharge of the bale from the baler. If the operator is not observing the progress of bale growth, and if the baler does not have an overfill protection feature, it is possible for the operator to supply an excessive amount of crop material to the bale-forming chamber and to form a bale having a diameter exceeding the capacity of the baler.
It is an object of the present invention to provide a round baler with a selectively engageable pickup drive system which performs the dual function of overload and overfill protection for the baler, to prevent operation of the pickup mechanism in the event of either an overload or an overfill condition. It is a further object of the invention to provide such a system which reliably disengages the pickup drive system so as to ensure that operation of the pickup mechanism is stopped immediately when an overfill or overload condition occurs. It is a further object of the invention to provide such a system which can be employed without significant alterations in the basic design and operation of the components of the baler. Yet another object of the invention is to provide such a system which is capable of being used in combination with a chain and sprocket drive system for transferring power to the pickup mechanism. A still further object of the invention is to provide such a system which is relatively simple in its components and operation, yet which functions in an effective manner to selectively disable the pickup of the baler.
In accordance with the invention, a combination overload and overfill protection system for a round baler includes an input drive member which is normally rotated during operation of the baler. The input drive member may be in the form of a drive hub mounted to a support shaft which supports one of the rotatable rolls forming a part of the baler.
An input driven member, which may be in the form of an input sprocket, is rotatably mounted to the support shaft for movement independently of the input drive member. The input driven member may be in the form of a sprocket which is interconnected with a chain-type drive arrangement for transferring power to the pickup mechanism. A selectively engageable drive mechanism is interposed between the input drive member and the input driven member, and includes a shiftable engagement member mounted to one of the input drive member and the input driven member, and a fixed drive member engaged with the other of the input drive member and the input driven member. The shiftable engagement member is movable between an engaged position, in which the engagement member engages the fixed drive member, and a disengaged position in which the engagement member is moved out of engagement with the fixed drive member. During normal operation, the engagement member remains in engagement with the fixed drive member so as to rotate the input driven member in response to rotation of the rotatable input drive member.
An actuator mechanism includes a trip member and a latching member which is movable between a latching position and a release position. The baler includes a movable member which moves during bale growth within the bale-forming chamber. When the bale attains a predetermined maximum size within the bale-forming chamber, the movable member engages the latch member to move the latch member from its latching position to its release position. The actuator mechanism functions to move the trip member from an inoperative position to an operative position, in response to movement of the latch member to its release position. When the trip member is in its operative position, the trip member engages a lever interconnected with the engagement member of the selectively engageable drive arrangement, for moving the engagement member from its engaged position to its disengaged position. This functions to prevent the transfer of power from the rotatable input drive member to the input driven member, and to disable the pickup mechanism. Ejection of the bale from the bale-forming chamber functions to reset the actuator mechanism which returns the engagement member to its engaged position from its disengaged position, so as to allow subsequent bale formation and operation of the baler pickup drive system.
The fixed drive member is preferably in the form of a shear bolt with which the shiftable engagement member is engaged. In the event the pickup experiences an overload condition during operation, the overload force is applied to the head of the shear bolt through the shiftable engagement member. Application of an overload force above a predetermined threshold functions to shear the shear bolt, to immediately cut off power supplied to the pickup drive system and disable the pickup mechanism, to prevent further damage to either the drive system or other components of the baler. The operator then replaces the shear bolt in order to resume operation.
The invention further contemplates an improvement in a round baler and a method of operating a round baler, substantially in accordance with the foregoing summary.